Tune in to "Showbiz Tonight" tonight on HLN at 5 p.m. & 11 p.m. ET for the latest on why Demi Lovato is seeking treatment

Los Angeles, California (CNN) -- Disney star Demi Lovato had an "altercation" with a dancer on her concert tour before dropping out of the show to seek help with what her publicist called "emotional and physical issues," a source close to Lovato's camp said Tuesday.

Lovato left the world tour with the Jonas Brothers and checked into an inpatient treatment center last weekend, a statement released by her publicist said Monday.

The altercation with the dancer, which the source did not describe, may have led to Lovato's decision to leave, the source said.

The same source denied media reports that Lovato fought with actress Ashley Greene, the current girlfriend of Joe Jonas.

Lovato recently suffered a public end to a short romance with Jonas, one of the three brothers she had been traveling the world with.

"Demi Lovato left her tour early this weekend in order to seek medical treatment for emotional and physical issues she has dealt with for some time," the publicist's statement said.

The publicist cautioned against describing the treatment as "rehab."

"Demi has decided to take personal responsibility for her actions and seek help," the statement said. "She is doing just that."

The entourage was scheduled to perform in Chile, Brazil and Argentina over the next two weeks.

"She regrets not being able to finish her tour, but is looking forward to getting back to work in the near future," the statement said.

No act will be added to replace Lovato on the tour, which has only six shows remaining, a source close to the Jonas Brothers said.

The 18-year-old singer-actress has talked extensively about being bullied while in middle school.

"People say sticks and stones may break your bones, but names can never hurt you, but that's not true," Lovato wrote on a anti-bullying website last month. "Words can hurt. They hurt me. Things were said to me that I still haven't forgotten."

Along with her solo music career, Lovato co-starred in Disney's "Camp Rock" movies. She also has the lead role in Disney's TV series "Sonny With a Chance."